This invention relates generally to threaded caps and containers. More particularly, the invention relates to caps and containers that are tamper evident in the sense that any tampering with the cap when sealed to the container is clearly visible.
Tamper-evident caps ("closures") and related containers are used to indicate to a prospective purchaser whether the container has been tampered with. Several approaches are in use, ranging from tear bands whose removal indicates a cap has been unthreaded to plastic shrink bands that must first be torn off to unscrew the cap.
One drawback of many of these prior approaches is the need for special capping machinery in order to mount the tamper-evident cap to the container. Conventional capping machinery, especially where the containers are glass, simply threads the cap onto the container. For example, caps that use a snap ring below the threads, such as the tamper-evident cap shown and described in U.S. Pat. No. 4,984,701, cannot be used by industry-standard bottle capping machinery that is designed for mounting conventional caps, lids, etc. The cap therein must be heated for expansion before applying it to the container, and the cap must be initially pressed onto the container before it can be threaded. Conventional capping machinery lacks means for heating or pressing a cap onto a container. Rather, special capping machinery of a significant cost is required to mount such caps to containers.
Another drawback of prior tamper-evident caps is that many require a container neck that cannot be easily blow molded, a common method of molding glass containers. Plastic containers such as milk jugs may be blow molded with less heat and pressure, allowing many diverse and multiple angles. But glass containers, which are preferable for storing many types of food products, generally cannot be molded in a way that allows many diverse and multiple angles due to the propensity of glass to break rather than bend. For example, U.S. Pat. No. 4,131,212 shows and describes a container and closure that uses complementary rachet teeth to lock the closure to the container. But the shape number and arrangement of the teeth requires that the container be made by injection molding onto a blank of flexible sheet material. Glass containers cannot readily be made in this manner.
Another drawback of most tamper evident closures is the ease with which a tamperer can reclose a container and mask the tampering, because the container still holds the separated portions in their approximately untampered relationships.
The tamper-evident cap that is the subject of the present invention suffers from none of these drawbacks. It can be mounted with conventional capping machinery onto a complementary container. And the container may be readily blow molded made from glass as well as made from other materials.